SARS-CoV-2 1,000 times more contagious than the closest relative

SARS-CoV-2, the virus that causes Covid-19, developed after a study after several different coronaviruses merged into one.

Scientists came to the conclusion when they were trying to understand the evolutionary history of the coronavirus to make a vaccine.

High-resolution images show that the tip on the surface of SARS-CoV-2 is 97 percent identical to the tip on the coronavirus to which it is most similar, called RaTG13, which is found in bats.

However, the slight differences make SARS-CoV-2 far more stable and 1000 times better in binding to a receptor on human cells called ACE2, as a study shows.

ACE2 has been called the "key to entry" for the human body, and the mutations on the tip of SARS-CoV-2 make it a perfect fit.

Researchers at the Francis Crick Institute in London say that their results do not help clarify the origin of the virus, which killed more than half a million people.

However, these latest research results show that the virus has developed naturally over time and was not man-made.

China has repeatedly denied allegations that the corona virus was generated in a laboratory in Wuhan City, where the pandemic started in December.

And officials from the World Health Organization have contested the claims several times, claiming that there is no evidence that the new corona virus was produced in a laboratory.

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In the picture the SARS-CoV-2 virus tip as picture of the team of the Francis Crick Institute

Coronavirus has tips on its surface that help them to infect cells. The tip of SARS-CoV-2 (right), the virus that causes the current pandemic, is very similar to the tip of another coronavirus in bats (left). However, it is 1000 times better at infecting human cells

A team of researchers at the Francis Crick Institute in London used a technique called cryo-electron microscopy to create the most detailed image of the tip of the coronavirus ever recorded.

The tip on the surface has been a target of scientists for several months as it controls how the virus evades the immune system and infects cells.

Using cryo-electron microscopy, the scientists compared SARS-CoV-2 with its closest known relative, RaTG13.

RaTG13 is unlikely to be harmful to humans, the researchers say, and is unlikely to infect our cells through the ACE2 receptor.

The spikes are both called proteins, some of which consist of sugar and are used by cells for communication and interaction.

Both different corona viruses had peaks that were almost identical in shape and structure, but only for a handful of minor modifications.

However, these small differences had a strong impact on the infectivity of the virus in humans and made it 1000 times better at penetrating human cells.

Antoni Wrobel, co-lead author of the study, said: & # 39; The spike is the input key that enables SARS-CoV-2 into human cells.

"Changes in the genome of the virus" that affect the structure of the spike can therefore result in the virus being able to penetrate more or less into the host's cell. "

Covid-19 causes delirium, stroke and nerve damage

Infection with the coronavirus can lead to delirium, stroke and nerve damage in a “number of patients above expectations”, according to a study.

University College London experts have reported a "worrying surge" amid the pandemic rare brain inflammation known to be caused by viral infections.

Typically in children, acute disseminated encephalomyelitis – ADEM for short – affects both the brain and the spinal cord.

In this condition, which can be due to minor infections such as colds, immune cells are activated to attack the fat protection layer that covers the nerves.

The researchers warned that doctors need to be aware of the risk of neurological effects in order to make early diagnoses and improve patient outcomes.

"At some point in the development of this virus, it appears to have picked up changes, such as the differences that we have identified and that have enabled it to infect people."

How exactly the novel SARS-CoV-2 coronavirus developed remains a mystery, but researchers in the latest study say that the most likely explanation is that several different viruses have fused together.

A first theory that scientists constructed to explain how the coronavirus originated was that a coronavirus in bats was passed on to an intermediate host, possibly pangoline, and infected humans from here.

Another theory is that the virus jumped directly from bats to humans in a damp market in Wuhan.

Bats are largely immune to coronaviruses and a reservoir for dozens of viruses. However, you can rarely jump from one species to another.

Understanding how SARS-CoV-2 has made this transition and how it has evolved is important information that could help scientists develop a vaccine.

Donald Benton, another co-lead author of the study, says: “The exact process of developing SARS-CoV-2 is still unclear and is being put together by many researchers.

"Our work provides a piece of this puzzle because it suggests that the virus does not come directly from the currently known bat corona viruses."

Steve Gamblin, group leader of the Structural Biology of Disease Processes at the Francis Crick Institute, added: “The world was surprised by SARS-CoV-2.

"Studying the structure of this virus and its likely predecessor helps us understand where it came from and how it interacts with human cells."

The full results have been published in Nature Structural & Molecular Biology.

Surface tips enable the coronavirus to bypass the immune system

The SARS-CoV-2 virus has a large number of spines which protrude from its surface and which serve to bind to and penetrate cells in the human body.

These spikes are coated with sugar, the so-called glycans, which disguise their viral proteins and help them dodge the body's immune system.

"When coated with sugar, viruses are like a wolf in sheep's clothing," said Professor Crispin.

The corona virus has a relatively low sugar shielding.

The lower glycan density means that the immune system has fewer obstacles to neutralize the virus with antibodies.

Professor Max Crispin of the University of Southampton is also examining the top to learn more about the virus.

In April, he created one of the first 3D models of the virus, showing the large number of tips on the outside.

He found that the spikes, which are made of sugar, enable him to sneak into the body undetected and behave "like a wolf in sheep's clothing," the researchers say.

However, the researchers found that the novel corona virus is not as well protected or camouflaged as some viruses like HIV.

According to Professor Crispin, a large number of spines protrude from the surface of Sars-CoV-2, with which they attach to and penetrate cells in the human body.

These spikes are coated with sugar, the so-called glycans, which disguise their viral proteins and help them dodge the body's immune system.

Professor Crispin said earlier: “When coated with sugar, viruses are like a wolf in sheep's clothing.

"One of the key results of our study, however, is that despite the high levels of sugar, this corona virus is not as shielded as some other viruses.

“Viruses like HIV that hang around in a host have to constantly dodge the immune system and have a really dense layer of glycans as a protective shield for the immune system.

"But in the case of the corona virus, the lower shielding from sugar attached to it may indicate that it is a" hit and run "virus that moves from one person to another.

However, the lower glycan density means that the immune system has fewer obstacles to neutralize the virus with antibodies. So this is a very encouraging message for vaccine development. & # 39;

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